Polycarbonate resins are used as thermoplastic resins having excellent impact resistance, heat resistance and transparency in a wide variety of applications, such as interior panels for vehicles, headlamp lenses for vehicles, and housings for mobile phones, mobile terminals, liquid crystal televisions and personal computers, and are also used as vehicle windows and the like due to exhibiting excellent productivity and being lighter than inorganic glasses.
In addition, sheets and films that use polycarbonate resins are also widely used, additional processing such as laminate formation and hard coat treatment is often carried out using such sheets and films, and such sheets and films are also widely used as a variety of components for a variety of display devices, interior parts for vehicles and components for protective devices.
However, currently used polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane, otherwise known as bisphenol A, exhibit excellent mechanical characteristics, but exhibit low surface hardness, which is represented by pencil hardness (the pencil hardness of polycarbonate resins derived from bisphenol A is 2B).
Many polycarbonate resins and polycarbonate resin compositions have been proposed in the past in order to improve the surface hardness of polycarbonate resins.
For example, Patent Document 1 reports that a high surface hardness corresponding to a pencil hardness of 2H can be achieved by means of a copolycarbonate of dimethylbisphenolcyclohexane and bisphenol A.
Furthermore, a composition obtained by blending a silicone oil in a polycarbonate resin (Patent Document 2), a composition obtained by blending a sliding filler such as a silicone compound (Patent Document 3) and a composition obtained by blending an antiplasticizer such as a biphenyl compound, a terphenyl compound or a polycaprolactone (Patent Document 4) have been reported as resin compositions having high surface hardnesses.
However, these polycarbonate resins certainly exhibit improved surface hardness, but are still unsatisfactory in, for example, outdoor applications where weathering resistance is required or applications where even higher surface hardness and abrasion resistance are required.
In addition, Patent Document 5 discloses an invention of a polycarbonate resin composition which exhibits good light conductivity and which is obtained by blending an acrylic resin having a molecular weight of 200-100,000 in a polycarbonate resin, and proposes using this polycarbonate resin composition in a light guide plate.
However, this type of polycarbonate resin composition exhibits reduced impact resistance, heat resistance and transparency, and readily whitens during molding, and it was found that this whitening becomes remarkably worse during high speed molding carried out at speeds of, for example, 200 mm/sec or higher, or when forming a thin wall molded article, or when forming a molded article having a part shaped in such a way that the shear rate increases during resin filling.